British Prime Minister Boris Johnson was fined in connection with the police investigation into illegal parties and gatherings held at his residence and other government premises during coronavirus-induced lockdowns, Downing Street confirmed Tuesday.

Johnson is the first sitting prime minister in U.K.’s history to have broken the law while in office.

Johnson, his wife, Carrie, and the Chancellor of the Exchequer Rishi Sunak have all been handed fines in connection with a host of lockdown breaches reported last year. Details as to how much the fines were worth, or which gatherings they were issued in connection with, were scant.

“The Prime Minister and the Chancellor of the Exchequer have today received notification that the Metropolitan Police intend to issue them with fixed penalty notices,” a Downing Street spokesperson said in a statement. “We have no further details, but we will update you again when we do.”

The investigation into a number of events held at Downing Street by the prime minister’s staff while the country was under lockdown conditions dominated headlines earlier this year. U.K.’s Metropolitan Police Service announced it was investigating at least eight gatherings, and they were currently examining over 500 documents and 300 images provided to them by a separate, internal investigation led by top civil servant, Sue Gray.

A number of gatherings during lockdown took place at government residences, including a Christmas event, two leaving parties for departing staff and a summer gathering in the Downing Street garden, where up to 100 staffers were invited to bring their own alcoholic drinks. The Prime Minister has previously denied any wrongdoing, though recieved backlash for saying he believed that one of the gatherings, where pictures were leaked to the press of staff drinking alcohol, was a “work event.”

The announcement that Johnson and Sunak are to be issued with fixed penalty notices — fines which must be paid to avert criminal proceedings — came a day after the Metropolitan Police announced an update to their investigation, saying at least 50 people have been fined so far.

Though media attention soon turned to the prime minister’s handling of the crisis in Ukraine, where he has taken a strong line against Russia and was recently pictured with Ukrainian President Volodymyr Zelenskyy in Ukraine’s capital, Kyiv, the announcement of the fines has led to fresh calls for his resignation.

While Parliament is in recess, the leader of the opposition Labour Party, Sir Keir Starmer, has already called for both Johnson and Sunak to resign.

“Boris Johnson and Rishi Sunak have broken the law and repeatedly lied to the British public,” he posted on Twitter. “They must both resign. The Conservatives are totally unfit to govern. Britain deserves better.”